xref: /openbmc/linux/arch/x86/mm/testmmiotrace.c (revision ff3a3e9ba5e4273a8bc10570adab4a390fb90757)
1*ff3a3e9bSPekka Paalanen /*
2*ff3a3e9bSPekka Paalanen  * Written by Pekka Paalanen, 2008 <pq@iki.fi>
3*ff3a3e9bSPekka Paalanen  */
4*ff3a3e9bSPekka Paalanen #include <linux/module.h>
5*ff3a3e9bSPekka Paalanen #include <asm/io.h>
6*ff3a3e9bSPekka Paalanen 
7*ff3a3e9bSPekka Paalanen #define MODULE_NAME "testmmiotrace"
8*ff3a3e9bSPekka Paalanen 
9*ff3a3e9bSPekka Paalanen static unsigned long mmio_address;
10*ff3a3e9bSPekka Paalanen module_param(mmio_address, ulong, 0);
11*ff3a3e9bSPekka Paalanen MODULE_PARM_DESC(mmio_address, "Start address of the mapping of 16 kB.");
12*ff3a3e9bSPekka Paalanen 
13*ff3a3e9bSPekka Paalanen static void do_write_test(void __iomem *p)
14*ff3a3e9bSPekka Paalanen {
15*ff3a3e9bSPekka Paalanen 	unsigned int i;
16*ff3a3e9bSPekka Paalanen 	for (i = 0; i < 256; i++)
17*ff3a3e9bSPekka Paalanen 		iowrite8(i, p + i);
18*ff3a3e9bSPekka Paalanen 	for (i = 1024; i < (5 * 1024); i += 2)
19*ff3a3e9bSPekka Paalanen 		iowrite16(i * 12 + 7, p + i);
20*ff3a3e9bSPekka Paalanen 	for (i = (5 * 1024); i < (16 * 1024); i += 4)
21*ff3a3e9bSPekka Paalanen 		iowrite32(i * 212371 + 13, p + i);
22*ff3a3e9bSPekka Paalanen }
23*ff3a3e9bSPekka Paalanen 
24*ff3a3e9bSPekka Paalanen static void do_read_test(void __iomem *p)
25*ff3a3e9bSPekka Paalanen {
26*ff3a3e9bSPekka Paalanen 	unsigned int i;
27*ff3a3e9bSPekka Paalanen 	for (i = 0; i < 256; i++)
28*ff3a3e9bSPekka Paalanen 		ioread8(p + i);
29*ff3a3e9bSPekka Paalanen 	for (i = 1024; i < (5 * 1024); i += 2)
30*ff3a3e9bSPekka Paalanen 		ioread16(p + i);
31*ff3a3e9bSPekka Paalanen 	for (i = (5 * 1024); i < (16 * 1024); i += 4)
32*ff3a3e9bSPekka Paalanen 		ioread32(p + i);
33*ff3a3e9bSPekka Paalanen }
34*ff3a3e9bSPekka Paalanen 
35*ff3a3e9bSPekka Paalanen static void do_test(void)
36*ff3a3e9bSPekka Paalanen {
37*ff3a3e9bSPekka Paalanen 	void __iomem *p = ioremap_nocache(mmio_address, 0x4000);
38*ff3a3e9bSPekka Paalanen 	if (!p) {
39*ff3a3e9bSPekka Paalanen 		pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
40*ff3a3e9bSPekka Paalanen 		return;
41*ff3a3e9bSPekka Paalanen 	}
42*ff3a3e9bSPekka Paalanen 	do_write_test(p);
43*ff3a3e9bSPekka Paalanen 	do_read_test(p);
44*ff3a3e9bSPekka Paalanen 	iounmap(p);
45*ff3a3e9bSPekka Paalanen }
46*ff3a3e9bSPekka Paalanen 
47*ff3a3e9bSPekka Paalanen static int __init init(void)
48*ff3a3e9bSPekka Paalanen {
49*ff3a3e9bSPekka Paalanen 	if (mmio_address == 0) {
50*ff3a3e9bSPekka Paalanen 		pr_err(MODULE_NAME ": you have to use the module argument "
51*ff3a3e9bSPekka Paalanen 							"mmio_address.\n");
52*ff3a3e9bSPekka Paalanen 		pr_err(MODULE_NAME ": DO NOT LOAD THIS MODULE UNLESS"
53*ff3a3e9bSPekka Paalanen 				" YOU REALLY KNOW WHAT YOU ARE DOING!\n");
54*ff3a3e9bSPekka Paalanen 		return -ENXIO;
55*ff3a3e9bSPekka Paalanen 	}
56*ff3a3e9bSPekka Paalanen 
57*ff3a3e9bSPekka Paalanen 	pr_warning(MODULE_NAME ": WARNING: mapping 16 kB @ 0x%08lx "
58*ff3a3e9bSPekka Paalanen 					"in PCI address space, and writing "
59*ff3a3e9bSPekka Paalanen 					"rubbish in there.\n", mmio_address);
60*ff3a3e9bSPekka Paalanen 	do_test();
61*ff3a3e9bSPekka Paalanen 	return 0;
62*ff3a3e9bSPekka Paalanen }
63*ff3a3e9bSPekka Paalanen 
64*ff3a3e9bSPekka Paalanen static void __exit cleanup(void)
65*ff3a3e9bSPekka Paalanen {
66*ff3a3e9bSPekka Paalanen 	pr_debug(MODULE_NAME ": unloaded.\n");
67*ff3a3e9bSPekka Paalanen }
68*ff3a3e9bSPekka Paalanen 
69*ff3a3e9bSPekka Paalanen module_init(init);
70*ff3a3e9bSPekka Paalanen module_exit(cleanup);
71*ff3a3e9bSPekka Paalanen MODULE_LICENSE("GPL");
72